Process for casting.



UNITED STATES PATENT OFFICE.

RICHARD .B. BROWNE, OF MASPETH, NEW YORK, ASSIGNOR TO RICHEY, BROWNE &

DONALD, 0F MASPETH, NEW YORK.

PROCESS FOR QASTING.

No Drawing.

Specification of Letters Patent. Patented Jan. 24, 1911. Application filed April 12, 1906. Serial No. 311,393.

To all whom 'it may concern:

Be it known that I, RICHARD B. Browns, a citizenof the United States, residing at Maspeth, in the borough of Queens and State of New York, have invented a new and useful Improvement in Processes for Casting, of which the following is a specification.

The invention relates to a process for reproducing or casting copies of models.

It is especially adapted for the artistic reproduction of the original modeling'in the fine arts, or in the decorative arts, where the original model is in'more or less high relief and undercut. The improvements may, however, if deemed desirable, be applied to the ordinary run of commercial foundry work regardless of the depth of the mold or the presence or absence of undercut features. I

For the purpose of illustrating one pract-ica'l application of the invention to the art of metal founding, it will be assumed that the original model to be reproduced is in alto-rehevo, or high relief, with deep and numerous undercut portions, the lines of which extend at various angles and curves.

In reproducing by casting the above model in iron,' bronze, or the like, a soft plastic negative mold (say a glue mold)- is first made, from wh ch, upon solidifying, the

model can be drawn intact from the'underout parts of the mold owing to its elasticity.

' Into this negative mold is then placed a friable composition, preferably in a wet state, which forms the pattern. After this pattern composition has set theelastic negative mold is drawn away from the pattern.

It generally stands a day or two to dry. After the pattern is removed from the elastic mold, it-is coated with a few coats of shellac, or other similar substance, for the purpose of surface hardening the pattern, and also for preventing any oil which may be in the molding sand from impregnating the pattern composition. The pattern thus formed may be used for any purpose or in any connection for which it may be found suitable.

" The pattern is, for example, peculiarly apgenerally have combined therewith a bindplicable for use in sand or molded-mold work, particularly-baked sand molds, which mg agent, such as oil. In such cases the friable pattern is molded in the sand in the usual way, and the mold with the pattern therein is put in a baking oven. The heat bakes and effects the hardening of the mold after the usual practice, and at the same time increases the friability of the composition of'the pattern.

After the mold isbaked an air current or other agent is ap lied to the pattern, which blows away the riable attern in the form of 'smallparticles and ust, whereupon the baked mold is ready for use for casting the destroyed pattern in molten metal.

The mold thus formed is not only capable of use in metal founding,.but in other kinds of casting or molding with plastic materials having the properties of setting or hardening in molds.

The material of which thepattern composition is formed is essentially a pnlverable friable substance, preferably mixed with Water. It has practically no, or very slight, tenacious quality, sufiicient only to enable it to hold its shape when molded. It is peculiarly susce tible after drying to disinteation, a shght molecular or mechanical isturbance, 511611, f01' example, as an air current, causing it to crumble and blow away. In other words, the pattern mixture is rotten and incapable of maintaining its molded form as a pattern when exposed to slight disturbances, The rotten pattern composition may be made of any substance or combination of substances which will have the characteristics above mentioned. composition having the above features can be made of about equal parts of powdered pumice stone and plaster of paris mixed with water, to which may be added alum or alum-Water. This composition in its wet state is not only friable, rotten and without material tenacious qualit but after being dried or baked is rendcre still more friable. After having been molded and set the exterior surface of the pattern ispainted or coated, (say with a few coats of shellac) in order to relatively harden the surface. The coating of the pattern permits it to be handled during the molding operations and also prevents any oily matter which may be incorporated in the molding sand from permeating the pattern and locally altering its degree of friability.

For example, one

Duplicates of the original molding may, M

of course, be made in the elastic negative V mold 1 makin What I claim is:

l. A foundry process which consists in makingya friable attern, then hardening the Surface thereof then making a mold from the pattern, and thereafter disintegrating the pattern before removing it from the mold.

2. A foundry process which consists in mold rom-\ the pattern, and then increasing the friability of the pattern when in th mold.

3. A foundry rocess consisting in form- 1ng a pattern 0 friable composition, then .hardening the surface'thereof, then forming a mold from the pattern, and finally baking the mold and pattern.

4. A foundry process which consists inmolding a friable pattern and baking the mold and pattern together.

tern, baking the mold and pattern to inafriable pattern, then making a crease the friabilityof the latter, and finally crumbling away the pattern from the mold.-

breaking up the pattern and removing it from the mold. v

9. A process which consists'of making a friable pattern, forming a mold on the pattern and then disinte rating the pattern leaving the mold ready or casting. v 10. A process which consists of making a friable pattern, forming a mold on'the pattern and then disintegrating the'pattern within the mold andremoving the fragments of the pattern leaving the mold ready for casting. v I

In testimony whereof I have affixed my signature in the presence of two witnesses.

' RICHARD B. BROWVNEJ Witnesses:

J. D. Hose, F. AnUNonL. 

